<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <script>
        var num = prompt('请输入班级人数');
        var sum = 0;
        var avg = 0;
        for (var i = 0; i < num; i++) {
            var score = prompt(`请输入第${i + 1}个学生成绩`);
            sum += Number(score);
        }
        avg = sum / num;
        
        alert(`班级总成绩是${sum}`);
        alert(`班级平均成绩是${avg}`);
    </script>
    </script>
</body>
</html>